BRPI0808349A2 - PROCESS TO REDUCE FREE OXYGEN IN A GAS HYDROCARBON CURRENT AND APPARATUS FOR REDUCING FREE OXYGEN CONTENT OF A HYDROCARBON GAS CURRENT - Google Patents

Description

PROCESS TO REDUCE FREE OXYGEN IN A GAS HYDROCARBON CURRENT AND APPARATUS FOR REDUCING FREE OXYGEN CONTENT OF A HYDROCARBON GAS CURRENT

This invention relates to a process for removing oxygen free from gaseous hydrocarbons.

Gaseous hydrocarbons such as natural gas, LPG or LNG may contain small amounts of free oxygen, ie O2 gas. Free oxygen may be inadvertently introduced by the use of a gaseous hydrocarbon as extraction gas or by mixing with air. For example, natural gas may contain free oxygen as a result of poor after-service purge, air leakage in compressor pumps, the use of natural gas as an extraction gas for gas dryers, the use of natural gas as an extraction gas. for injection of water and dissolved air into the fluids injected into the borehole. The amount of free oxygen in the natural gas recovered from these processes may be in the range of 70 to 100 ppm (vol). Alternatively, free oxygen can be introduced into LPG or LNG by combining processes with air to reduce the caloric value of the so-called "air balance". The amount of free oxygen introduced into LPG or LNG in this form can be as much as 0.5% by volume or greater.

The presence of free oxygen is potentially dangerous, although the main concern in processing free oxygen-containing gaseous hydrocarbons is the corrosion of process equipment, resulting in costly replacement and maintenance. In addition, free oxygen may react with hydrogen sulphide that may be present in the gas to form elemental sulfur, but it may also cause damage to molecular sieves used for gas drying by exothermic reaction with carbon residues. Free oxygen can cause undesirable oxidation of glycol-based solvents used in plant drying, or cause thermally stable salts to form in acid gas removal systems, leading to purge stream effluent problems. It is therefore desirable to limit the free oxygen content to a few ppm or less.

Direct combustion of free oxygen by heating the gaseous hydrocarbon over a combustion catalyst requires temperatures of 3000C or more and is not practical for heating large volumes of gas to this temperature and then cooling it for subsequent use.

We have created a process that solves these problems.

Accordingly, the invention provides a process for reducing free oxygen in a gaseous hydrocarbon stream, comprising the step of passing the gaseous hydrocarbon stream over a material comprising a metal selected from Ni, Co, Cu, Fe, Mn or Ag in a reduced state, so that oxygen present in said current reacts with the metal, whereby the metal in the reduced state is formed by,

(i) withdrawal of part of the hydrocarbon stream,

(ii) formation of a hydrogen-containing gas mixture of the hydrocarbon part and

(iii) passing the hydrogen-containing gas mixture over the metal-containing material in reduced form. By "reduced state" means that the metal is in the form of a lower oxide or an elemental form such that it is oxidizable by free oxygen in metal oxide or a higher valence metal oxide. In addition, "in reduced form" means that metal is in oxidized state, for example metal oxide.

The hydrogen-containing gas mixture may be catalytic dehydrogenation (cDH) of C2 + alkanes in the hydrocarbon over oxidized or precious metal catalysts to generate hydrogen and olefins. By "C2 + alkanes" means alkanes of formula CnH2n +2 with n2, preferably one or more of ethane, propane, butane, pentane and hexane. The main types of alkane dehydrogenation catalysts are Group 8 metals; particularly platinum / tin supported on ZnAl2O4, MgAl2O4 or alumina, chromium oxides in alumina or zirconia and gallium, or as a support oxide or present in zeolites. Light paraffins are better dehydrogenated using alumina promoted Pt / Sn and Cr2O3 over alumina above 500 ° C, preferably above 600 ° C. Long chain paraffins are better dehydrogenated using Pt / Sn promoted in alumina at temperatures between 400-500 ° C. While effective in forming hydrocarbon hydrogen in order to maintain activity, periodic regeneration of the catalyst with air may be required to burn carbon (coke) deposits.

The hydrogen-containing gas mixture may comprise one or more gases which are inert on the metal-containing material in reduced form, such as nitrogen or may comprise another reducing gas. Preferably, the hydrogen containing gas further comprises carbon monoxide. For example, a gas mixture containing hydrogen and carbon monoxide may be formed by partial combustion of hydrocarbons. Partial combustion of the hydrocarbon with an oxygen containing gas such as air, oxygen or oxygen enriched air produces a mixture of hydrogen and carbon monoxide containing gas as well as other gases such as unreacted C2 + hydrocarbons, methane, carbon dioxide and nitrogen. Partial combustion, also called partial oxidation, may have perhaps been performed using any known partial oxidation process. Hydrocarbon partial combustion may be performed by combustion of the flame in a burner using an oxygen-containing gas in the absence of a combustion catalyst called non-catalytic partial oxidation (POx), or preferably may be performed at lower temperatures in a presence of a partial oxidation catalyst called catalytic partial oxidation (cPOx). In cPOx, the catalyst is preferably a supported Ni, Rh, Pd or Pt catalyst having <20 wt% metal or alloy combinations of these metals on an inert support such as alumina, silica, titania and zirconia. a Rh or PtRh catalyst, on supports containing ceria.

Alternatively, a hydrogen and carbon monoxide-containing gas mixture may be formed by autothermal reforming (ATR) comprising oxidizing a hydrocarbon, generally a gaseous hydrocarbon, with an oxygen-containing gas in the presence of vapor, and steam reforming the gas mixture. resultant containing unreacted hydrocarbon on a steam reforming catalyst to produce a mixture of gas containing hydrogen and carbon oxides (carbon monoxide and carbon dioxide). In autothermal reforming, therefore, steam may be added with the hydrocarbon and / or oxygen containing gas. Oxidation step 5, which can be performed catalytically, is exothermic and generates the heat required by endothermic steam reforming reactions. Precious metal oxidation catalysts are preferred. Catalysts used in hydrocarbon reforming may include one or more than 10 Ni, Pt, Pd, Ru, Rh and Ir supported at levels up to 10% by weight on oxide supports such as silica, alumina, titania, zirconia, ceria, magnesia. or other suitable refractory oxides, which may be in the form of pellets, extrudates, cellular ceramics and / or metal monolith (honeycomb) or ceramic foam or other supporting structures that offer mechanical strength and slight pressure drop. In a preferred embodiment, the steam reforming and oxidation reactions are catalyzed, more preferably over the same catalyst composition such that a catalyst provides both functions. Such catalysts are described in WO 99/48805 and include Rh and Pt / Rh on refractory supports comprising mixtures containing Ce and / or Ce / Zr. The process may be operated at inlet temperatures in the range 25 0 - 550 ° C and

2 5 outlet temperatures in the range 500-800 ° C, depending on preheat amount and 02: C: H20 ratio, and when operated prior to a compression phase, pressures up to typically about 0.3 MPa abs . After compression, the pressure can be up to 15 MPa abs or higher.

As with combustion and steam reforming reactions, the water-gas exchange reaction occurs on the reforming catalyst. Thus, reactions that occur in an autothermal reformer where the hydrocarbon comprises methane include;

5 CH4 + 2 O2 - CO2 + 2 H2O

CH4 + H2O - CO + 3 H2 CO + H2O - * · CO2 + H2

However, autothermal overhaul requires a water supply for steam generation, which may not be practical, eg in offshore installations. In such cases, hydrogen formation by CDH, POx or CPOx may be preferred. Alternatively, a water recycling system in which no reacted vapor is condensed from the hydrogen-containing gas and recycled to reform step 15 may be employed.

While a gas mixture containing hydrogen and carbon monoxide may be formed by steam reforming only, this is not preferred.

If desired, the reformed gas mixture containing 20 hydrogen, steam and carbon oxides (CO and CO2) may be cooled and passed through a water-gas exchange catalyst that reacts carbon monoxide with steam to increase the hydrogen content in the gas. gas mixture according to the following equation.

CO + H2O «-> H2 + CO2

The water-gas exchange catalyst can be precise metal based, iron based or copper based. For example, a particulate alumina-copper-xzinc low temperature exchange catalyst containing 25-35% by weight of

30 CuO, 30-60 wt% ZnO and 5-40 wt% Al 2 O 3 may be used at temperatures in the range 200-250 ° C. Alternatively, the water-gas exchange catalyst may be Pt on ceria or titania.

When it is desired to use a carbon monoxide-containing gas as the reducing gas, the water-gas exchange step may be omitted.

If hydrogen formation is by ATR, POx or cPOx, with or without the water-gas exchange reaction, it may be desirable to cool the resulting gas mixture before contacting the reduced metal-containing material. Preferably, the temperature of the gas mixture is <300 ° C, more preferably <200 ° C, more preferably> 150 ° C when it is contacted with the metal-containing material in reduced form. Gas mixture cooling can be accomplished using technology known as heat exchanger. For example, the gas mixture can be cooled using high pressure water at medium to high vapor pressure generation.

The reduced state metal-containing material is formed by passing the hydrogen-containing gas mixture over the material. The metal-containing material in reduced form may also have potential as a catalyst and therefore may also be called a catalyst. The hydrogen-containing gas mixture may be continuously or periodically passed to the material as required to maintain sufficient activity to remove or reduce the amount of free oxygen, for example 5 ppm or less. Preferably, the hydrogen-containing gas mixture periodically passes to the reduced metal-containing material. For example, in the beginning, a part of the free oxygen-containing hydrocarbon is removed and used to form the hydrogen-containing gas mixture which is then used to reduce Co, Ni, Cu or Fe material to active form. The free oxygen containing hydrocarbon may then be passed through the reduced material for a period of time which may be days or months, depending on the free oxygen content of the hydrocarbon. The free oxygen content of the hydrocarbon passing through the material can be continuously monitored to the point at which the material is required to be regenerated can be determined. For regeneration, a part of the free oxygen containing hydrocarbon is removed and used to generate the hydrogen containing gas which is used to further reduce the material. Ni, Co, Cu, Fe, Mn or Ag in the material may be in the form of elemental oxide or lower. One or more reduced metals may be present. Preferably the metal is in elemental form. Free oxygen present in the hydrocarbon may be removed from the hydrocarbon by oxidation reactions. Oxidation reactions may proceed according to the following equations;

M O2 + M -> MO, (where M = Ni, Co, Cu, Fe and Ag in elemental form).

Already O2 + 3 CoO - »Co3O4% O2 + 2 FeO - * Fe2O3

2 5 Yt O2 + MnO - + MnO2

The material may include Ni, Co, Cu, Fe, Mn or Ag supported on a suitable solid support. The effectiveness of the material in the formation of the respective oxide, and its subsequent reduction back to metal, can be strongly influenced by the choice of support. Preferred supports include alumina, including transition alumina, silica, titania, zirconia, ceria, zinc oxide and combinations thereof. More suitable and less suitable combinations of reduced metal and support are known. For example, the formation of Co aluminate spinels may, if formed under oxidation conditions, reduce the oxide's ability to be reduced.

The material may be particulate or in the form of foam, monolith or coating on an inert support.

The reduced metal containing material is preferably a

copper material. For example, the material may include>

20% by weight of Cu. More preferably the metal-containing material in reduced form is a particulate copper-zincalumine material containing 25-35 wt% CuO, 30-60 wt% ZnO and 5-40 wt% Al2O3.

Alternatively, the material may be a finely divided iron material. All materials may optionally include precious metal promoters that may assist in the reduction process.

The oxidation of Ni, Co, Cu, Fe, Mn or Ag reduced by

Free oxygen present in the hydrocarbon is preferably ^ 300 ° C, more preferably ^ 200 ° C, most preferably ^ 150 ° C, especially <100 ° C, for example between -10 and 100 ° C.

In the present invention, a portion of the side chain of

Free oxygen-containing gaseous hydrocarbon is continuously or periodically withdrawn, for example, from a pipeline used to form a hydrogen-containing gas mixture by ATRi CDH, POx or cPOx and such mixture optionally following a gas-water exchange step, passed over the reduced metal containing material. The side stream withdrawal volume is preferably just sufficient to generate the sufficient hydrogen and / or carbon monoxide required to reduce the reduced metal in the material. The withdrawal of the part is therefore preferably ≤ 20%, more preferably ≤ 10%, more preferably ≤ 5% by volume of the gaseous hydrocarbon stream. A portion of the hydrogen-containing gas may desirably be subjected to a hydrogen separation step, for example using suitable membrane technology, and the recovered hydrogen sent upstream, for example for hydrogen disulfurization purposes.

In a preferred embodiment, the free oxygen containing hydrocarbon is natural gas, i.e. a methane rich gas stream containing small amounts of C2 + hydrocarbons. Natural gas may be a "pure" natural gas as recovered from underground sources or it may be a "process" natural gas that has been used in a process such as an extraction gas. Gas liquids

20 Natural (LGNs) may also be used.

If desired, sulfur and optionally mercury or arsenic absorbers may be provided, for example, in the hydrogen generation step, to remove poisons from the hydrocarbon used to form the hydrogen-containing gas and thus protect any catalysts used therein from poisoning. . Suitable sulfur absorbers include zinc oxide compositions, preferably copper-containing zinc oxide compositions, while mercury and arsenic are absorbed in a suitable manner.

30 useful in metal sulfides such as copper sulfide. Particularly suitable mercury and sulfur absorbers are described in EP 0.243.052 and EP 0.480.603. In addition, hydrogen desulfurization can also be carried out by tackling any adsorbents using known Ni or Co catalysts to convert organic sulfur, mercury and arsenic compounds into more easily removable materials such as H2S, NH3, Hg and AsH3.

While upstream sulfur removal may be desired to protect downstream catalysts, in cases where a precious metal reforming catalyst is employed upstream of a water exchange catalyst, it may be desirable in addition or as An alternative is to include a sulfur absorber between the reforming catalyst and the water-gas exchange catalyst.

In a particularly preferred process, a natural gas side stream is withdrawn and used to generate the hydrogen containing gas mixture.

The apparatus used for the process of the present invention may be conveniently compact, especially where partial combustion of the side stream is affected.

Thus, the invention further provides apparatus for reducing the free oxygen content of a gaseous hydrocarbon stream, comprising an oxygen scavenging vessel having gaseous hydrocarbon inlet means, gas outlet means as product, and a Ni material. Co, Cu, Fe, Mn or Ag disposed within said vessel, between said inlet and outlet means, whereby the hydrogen forming means is operatively connected to the free oxygen-containing gaseous hydrocarbon stream and said vessel such that said gas containing hydrogen can be passed over the material. The hydrogen forming means may comprise a catalytic dehydrogenation vessel having hydrocarbon inlet means, gas outlet means as product and containing a dehydrogenation catalyst disposed between the inlet and outlet means.

Alternatively, the hydrogen forming means may comprise an autothermal reformer having vapor and hydrocarbon inlet means, oxygen-containing one gas inlet means, gas outlet means as oxidizing means product and downstream said means. oxidation means a steam reforming catalyst, both arranged between said inlet and outlet means. Oxidation means may comprise a combustion burner or a partial oxidation catalyst.

Preferably the hydrogen forming means comprises a partial combustion vessel having oxygen and hydrocarbon containing gas inlet means, gas outlet means as a product and optionally containing a partial oxidation catalyst disposed between said inlet and outlet means. .

In one embodiment, a gas-water exchange vessel containing a gas-water exchange catalyst may be operatively connected between the partial combustion vessel or the autothermal reforming vessel and the oxygen removal vessel such that Gaseous product from the partial combustion vessel or the autothermal reforming vessel may be hydrogen enriched before being transferred to the oxygen removal vessel.

It is desirable that any apparatus used to generate hydrogen be compact in order to facilitate offshore as well as onshore installation. In particular, the exchange and reforming stages may be combined in a compact hydrogen generating apparatus in which a hydrocarbon and oxygen are combined over a precious metal partial oxidation catalyst, which may also function as a catalyst for the reforming reactions. steam, and the resulting reformed gas mixture cooled and passed over a water exchange catalyst. Cooling of the reformed gas mixture can be accomplished using heat exchange means such as coils, cooling plates and pipes or by direct injection of water. Thus, in a preferred embodiment, the hydrogen generating apparatus comprises a vessel in which a supported precious metal reforming catalyst and a pipe-supported water-gas exchange catalyst or heat exchange plate are arranged between the catalysts. The hydrocarbon is fed with a stream and oxygen containing gas to the reforming catalyst where reforming and oxidation reactions occur. The resulting reformed gas mixture containing hydrogen, carbon oxides and steam and a small amount of unreacted hydrocarbons is then cooled by coils or heat exchange plate and passed over the water-gas exchange catalyst to increase hydrogen content. of the hydrogen containing gas. The use of the hydrogen generating apparatus comprising both reforming and exchange catalysts is preferred as it is very compact and can therefore be easily installed offshore as well as onshore installations such as rigs. oil production. We have revealed that the reforming reforming apparatus designed for hydrogen generation as a fuel cell is particularly suitable for the present invention because of its relatively small size. Suitable apparatus for autothermal reforming is described in EP

0.262.947 and Platinum Met. Rev. 2000, 44 (3), 108-111, and is known as the HotSpot ™ reformer.

In the present invention, the hydrogen forming means is operatively connected to the oxygen containing gaseous hydrocarbon stream, so that the hydrogen forming means is fed with a free oxygen containing gaseous side hydrocarbon stream. Hydrocarbon flow from the side stream to the hydrogen forming media may be controlled by suitable valves.

If desired, suitable heat exchange means may be provided to cool the gaseous product stream from the hydrogen forming medium to avoid decomposition of the reduced metal material.

The invention is further illustrated by reference to the drawings in which Figure 1 is a flowchart of one embodiment of the process of the present invention and Figure 2 is a flowchart of an alternate embodiment wherein hydrogen generation and exchange reactions take place within it. vase.

In Figure 1, a natural gas containing 70-100 ppm free oxygen is fed through line 10 at room temperature to an oxygen removal vessel 12 where it passes through a bed of particulate supported reduced copper material 14. The level of free oxygen in product stream 16 leaving vessel 12 is reduced to <5 ppm and copper is oxidized. When the free oxygen content of the hydrocarbon passing through the copper material increases to> 5 ppm, an upstream side stream line 18 from vessel 12 is used to remove a portion of the oxygen-containing natural gas from line 10. The amount of natural gas withdrawn through line 18 is controlled by valves 20 in line 10 and 22 in line 18. The part withdrawn

20% by vol) is fed through line 18 to a partial combustion vessel 24 in which a precious metal partial oxidation catalyst 26 is disposed. Air is fed through line 28 to combustion vessel 24. Oxygen in the Air 28 reacts with the hydrocarbon feed on catalyst 26 to provide a gaseous product stream comprising hydrogen, carbon monoxide, steam and carbon dioxide. The gaseous product stream emerging from the combustion vessel 24 is cooled in heat exchanger 30 and then passed to the water-gas exchange vessel 32 containing a copper-based water-gas exchange catalyst bed 34. The content of hydrogen from the partially burnt gas stream is increased over the gas-water exchange catalyst. The hydrogen-enriched gas stream is passed from vessel 32 through heat exchanger 36 and line 38 to vessel 12 where it passes over oxidized copper material and reduces oxidized copper.

In Figure 2, a natural gas containing 70-100 ppm free oxygen is fed through line 10 at room temperature to remove an oxygen removal vessel 12, where it passes through a bed of particulate supported reduced copper material 14. The free oxygen level in the product stream 16 leaving vessel 12 is reduced to <5 ppm and copper is oxidized. When the free oxygen content of the hydrocarbon passing through the copper material increases to> 5 ppm, an upstream side stream 18 from vessel 12 is used to remove a portion of the oxygen-containing natural gas from line 10. The amount of natural gas withdrawal through line 18 is controlled by valves 20 in line 10 and 22 in line 18. The withdrawn portion (<20 vol%) is fed through line 18 into a 40 ° C purification vessel containing a copper oxide composition particulate zinc 42, which removes hydrogen sulfide from the gas stream. The desulfurized gas is then preheated by means of a heat exchanger (not shown) and fed through line 44 to hydrogen generating vessel 46 containing a monolithic Rh under cerium-doped zirconia reforming catalyst 48. Desulfurized gas is mixed with oxygen and steam fed to the hydrogen generating vessel 46 through line 50 and the autothermally reformed mixture (oxidized and reformed steam) over catalyst 48. The catalyst catalyzes both steam reforming reactions and combustion. The reformed gas stream comprising hydrogen, steam and carbon oxides is cooled by heat exchange tubes 52 into vessel 46 downstream of reforming catalyst 48. The cooled gases are then passed to an exchange catalyst bed at low temperature 54 disposed within vessel 46, downstream of said heat exchange tubes 52. The cooled gas mixture reacts on catalyst 54 to increase the hydrogen content in the gas mixture by the water-gas exchange reaction.

The hydrogen enriched gas stream passes from vessel 46 through line 56 to heat exchanger 36 and then line 38 to vessel 12 where it passes over oxidized copper material and reduces oxidized copper.

Claims (24)

Process for reducing free oxygen in a gaseous hydrocarbon stream, characterized in that it comprises the step of passing the gaseous hydrocarbon stream over a material comprising a metal selected from Ni, Co, Cu, Fe, Mn or Ag. in a reduced state such that oxygen present in said stream reacts with the metal, whereby the metal in the reduced state is formed by (i) withdrawing a portion of the hydrocarbon stream, (ii) forming a hydrogen-containing gas mixture (iii) passing the hydrogen-containing gas mixture over the metal-containing material in reduced form. Process according to Claim 1, characterized in that the hydrogen-containing gas mixture is formed in a catalytic dehydrogenation step on precious metal or oxide catalysts. Process according to Claim 1, characterized in that the hydrogen-containing gas mixture is formed by the autothermal reforming comprises a step of partially oxidizing a hydrocarbon / vapor mixture with an optionally oxygen-containing gas over a catalyst. oxidation and steam reforming of the resulting gas mixture directly onto a supported Ni bed or precise metal steam reforming catalyst. Process according to Claim 3, characterized in that the steam reforming and oxidation catalysts are both a supported precious metal catalyst. Process according to Claim 1, characterized in that the hydrogen-containing gas mixture is formed by the partial oxidation of hydrocarbon with an oxygen-containing gas. Process according to Claim 5, characterized in that the partial oxidation of hydrocarbon is carried out in the absence of a partial oxidation catalyst. Process according to Claim 5, characterized in that the partial oxidation of hydrocarbons is carried out in the presence of a partial oxidation catalyst. Process according to Claim 7, characterized in that the partial oxidation catalyst is a supported precious metal oxidation catalyst. Process according to any one of claims 3, 4, 5, 6, 7 or 8, characterized in that the hydrogen-containing gas mixture is subjected to the water-gas exchange reaction via an exchange catalyst. of water-gas to increase the hydrogen content in the gas mixture. Process according to any one of claims 1, 2, 3, 4, 5, 6, 7, 8 or 9, characterized in that the metal in the reduced state is formed periodically. Process according to any one of claims 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, characterized in that the free oxygen containing hydrocarbon is a natural gas, including natural gas. which has been used as extraction gas. Process according to any one of claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11, characterized in that the metal material is a copper material containing ^ 20% by weight of copper. Process according to any one of claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11, characterized in that the metal material is a finely divided iron material; optionally comprising the precious metal promoters. Process according to any one of claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or 13, characterized in that the free oxygen-containing hydrocarbon is passed over the metal material at a temperature ^ 300 ° C. Process according to any one of claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14, characterized in that sulfur absorbers and, optionally mercury or arsenic is provided upstream of the hydrogen formation step to remove poisons from the hydrocarbon used to form the hydrogen containing gas. Process according to any one of claims 9, 10, 11, 12, 13, 14 or 15, characterized in that a sulfur absorber is provided by the gas-water exchange catalyst. 17. Apparatus for reducing the free oxygen content of a hydrocarbon gas stream, characterized in that it comprises an oxygen removal vessel having free oxygen-containing gaseous hydrocarbon inlet means and gas outlet means as a product and a Ni, Co, Cu, Fe, Mn or Ag material disposed within said vessel between said inlet and outlet means, whereby the hydrogen forming means is operatively connected to the free oxygen-containing gaseous hydrocarbon stream and said vessel and that said hydrogen-containing gas may be passed over said material. Apparatus according to claim 17, characterized in that the hydrogen forming means comprises a catalytic dehydrogenation vessel having hydrocarbon-containing inlet means, gas-outlet means as product and containing a dehydrogenation catalyst disposed between the means of entry and exit. Apparatus according to claim 17, characterized in that the hydrogen forming means comprises an autothermal reformer having hydrocarbon inlet means, vapor inlet means, oxygen-containing gas inlet means, outlet means gas as a product and disposed between the inlet and outlet means, a partial oxidation means and a steam reforming catalyst. Apparatus according to claim 17, characterized in that the hydrogen forming means comprise a partial combustion vessel having oxygen and hydrocarbon gas inlet means, gas outlet means as product, and optionally containing a partial oxidation catalyst between said input and output means. Apparatus according to either of claims 19 or 20, characterized in that the water-gas exchange vessel containing a water-gas exchange catalyst is operably connected between the autothermal reformer or partial combustion vessel and the oxygen removal vessel so that product stream from the autothermal reformer or partial combustion vessel can be enriched with hydrogen before being transferred to the oxygen removal vessel. Apparatus according to claim 17, characterized in that the hydrogen forming means comprises a vessel having hydrocarbon inlet means, vapor and oxygen inlet means and gas outlet means as product and disposed between. the inlet and outlet means a partial oxidation catalyst, which may also function as a steam reforming catalyst, upstream of the cooling means, and a water-gas exchange catalyst downstream of said cooling means. Apparatus according to any one of claims 17, 18, 19, 20, 21 or 22, characterized in that control means are provided for the periodic removal of gaseous hydrocarbon to said hydrogen forming means. Apparatus according to any one of claims 17, 18, 19, 20, 21, 22 or 23, characterized in that the heat exchange means are provided for cooling the hydrogen-containing gas of the hydrogen forming media to avoid decomposition of free oxygen-containing gaseous hydrocarbon and to avoid damage to the water-gas exchange catalyst if present.